Since the national new energy promotion policy was implemented, pure electric commercial vehicle market continues to develop. A battery management system is one of key technologies related to practical use and commercialization of electric vehicles, so it has a great significance to research and develop battery management technologies and systems and to enable industrialization thereof.
At present, most pure electric vehicles are provided with a battery system including ten or more battery cases. Each battery case is equipped with a slave module of the battery management system. The slave modules are connected with each other by complicated low-voltage power supply and communication harnesses. In a case that the battery system has N battery cases, the connection between the master module and the slave modules requires more than N low-voltage connection harnesses and it also requires more than N connection nodes. A long-distance low-voltage trace results in a large voltage drop across the harness, and so many connection nodes may increase the risk of low-voltage harnesses and low-voltage connectors being loosen or damaged, which affects the battery management system's power supply and communication reliability. Moreover, a circuit, which has long distance, multiple nodes and high voltage, requires additional On-Off circuit detection and breaker point positioning.